4 Sprite Hardware / Displaying a Sprite

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After building the data structure , you need to tell the system to
display it. This section describes the display of sprites in
 automatic mode . In this mode, once the sprite DMA channel begins to
retrieve and display the data, the display continues until the VSTOP
position is reached. Manual mode is described later on in this chapter.
The following steps are used in displaying the sprite:
 1. Decide which of the eight sprite DMA channels to use (making certain
 that the chosen channel is available).
 2. Set the sprite pointers to tell the system where to find the sprite
 data.
 3. Turn on sprite direct memory access if it is not already on.
 4. For each subsequent display field, during the vertical blanking 
 interval, rewrite the sprite pointers.
 About sprite DMA.
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 If sprite DMA is turned off while a sprite is being displayed (that
 is, after VSTART but before VSTOP), the system will continue to
 display the line of sprite data that was most recently fetched. This
 causes a vertical bar to appear on the screen. It is recommended that
 sprite DMA be turned off only during vertical blanking or during some
 portion of the display where you are sure that no sprite is being
 displayed.
 Selecting a DMA Channel and Setting the Pointers 
 Resetting the Address Pointers 
 Sprite Display Example 

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